Wolves were reintroduced to Yellowstone National Park in 1995. They began to hunt the abundant elk
population, so elk numbers decreased. The elk carcasses provided food for other predators, like
foxes, coyotes, and bears, so all of their populations increased. Elk used to overgraze on willow
plants; now that willows are growing back, beaver numbers are increasing, because they prefer the
wolves
bears
willows
elk
Wolves, bears, willows, and elk are all interconnected in this ecosystem at Yellowstone National Park.
The reintroduction of wolves led to a decrease in the elk population because wolves are natural predators of elk. With fewer elk around, the carcasses of the prey that the wolves hunted became food for other predators like foxes, coyotes, and bears. Therefore, the populations of these predator species increased.
The decrease in elk also had a positive impact on the growth of willow plants. Elk used to overgraze on willow plants, limiting their growth. However, with a reduced elk population, willows started to grow back. This increase in willow plants created a favorable habitat for beavers. Beavers prefer willow plants as a food source and material for building dams, so their numbers began to increase as well.
Overall, the reintroduction of wolves to Yellowstone National Park had cascading effects on the populations of various species, creating a more balanced and diverse ecosystem.